What causes changes in fingernails?

All sorts of illnesses can make your fingernails look funny. Psoriasis and fungal infections are the most common problems with nails, causing them to grow thick and crack. But it's those lines that cross the nail, not run with the length of it, that are of real concern. These lines (called Beau's lines), start at the lunula and grow out with the nail. They can occur with syphilis, diabetes, heart disease, peripheral vascular disease, zinc deficiency, and after high fevers or after chemotherapy. And nails can become spoon-like with iron deficiency anemia, and the ends of the fingers can grow into clubs with lung and heart disease, cirrhosis and thyroid disease. Yellow nails can mean you have certain lung diseases or even AIDS. And the prettiest nails, called "Terry's nails" can mean you have diabetes, cirrhosis or heart failure. These nails are white or light pink and have a narrow normal pink band near the end of the fingernail.

Your fingernails can change for any number of reasons. Some changes, such as developing brittle nails, can come with age. Others may be a reaction to a medication or a sign of a more serious medical condition.

If you notice a significant change in your nails, talk to your doctor or dermatologist. He or she can determine whether an underlying condition might be the cause, whether you need medical treatment, and what you can do at home to improve your nail health.